The Student Room Group

AQA CHEM5 A2 Chemistry - 19th June 2013

Scroll to see replies

Original post by gooner1886
In the Jan 13 paper - q7 (b), for the cell represenation, why do they penalise you for writing down Pt?


The Fe and Cu serve as electrons, they aren't both aqueous so you dont need them
Well this is embarrassing i read it wrong. sorry guys. :smile: good luck everyone
Original post by Mistrykid
It was horrendous. So too was the Jan '13 paper I did earlier today:sad:


I know! I found those two to be the most difficult ones I've done.

Spoiler

Original post by fredstan5014
Guys, what do you need in this paper to get an A. maay seem dumb but all the ums calculator get contradicted by aqa scaled mark boundarys it seems :/


It's usually between 71 and 74 for an A.
Original post by brittanna
It's usually between 71 and 74 for an A.




Is it not close to 80 odd? Like Unit 2 and 4?
Reply 2185
Avatar for crc290
crc290
14
Original post by gooner1886
In the Jan 13 paper - q7 (b), for the cell represenation, why do they penalise you for writing down Pt?


Because Cu and Fe are solid, so you don't need a platinum electrode
Out of the two definitions for second ionization enthalpy, which would you pick?

1) The enthalpy change when one mole of electrons are lost from one mole of a gaseous 1+ ion to form a gaseous 2+ ion

2) The enthalpy change when one mole of gaseous 2+ ions are formed from one mole of gaseous 1+ ions
Original post by crc290
Because Cu and Fe are solid, so you don't need a platinum electrode


Original post by Kev.1995
The Fe and Cu serve as electrons, they aren't both aqueous so you dont need them



Ah. Thank you.
Original post by frogs r everywhere
BL acid is a proton donor
Lewis base is an electron donor

In the case of H+ and OH- ions, yes you are right. In the case of [Cr(H2O)6]3+ and ammonia-dropwise (to form NH4+ ions), no. The chromium complex may be a bronsted lowry acid, but is not a lewis base.


Thanks!


Posted from TSR Mobile
Reply 2189
Avatar for crc290
crc290
14
Original post by frogs r everywhere
Lewis base is an electron donor.

Original post by RoaringLion
Thanks!


Should just add that a Lewis base is an electron pair donor. Most mark schemes don't allow just 'electron donor'
Reply 2190
Avatar for Shalo1
Shalo1
11
HAS ANYONE GOT THE JANUARY 2013 PAPERR?! ( and mark scheme)
:frown:(((( cant find it anywhere

(Pretty please)


Posted from TSR Mobile
did anyone else think the Jan 2013 paper was hard? I just did it and I couldnt answer some of the questions, Like the "calculate the bond enthalpy for the Cl-F bond" I couldnt even remember how to do that :frown:
Reply 2192
Avatar for saba146
saba146
Original post by Affliction
Out of the two definitions for second ionization enthalpy, which would you pick?

1) The enthalpy change when one mole of electrons are lost from one mole of a gaseous 1+ ion to form a gaseous 2+ ion

2) The enthalpy change when one mole of gaseous 2+ ions are formed from one mole of gaseous 1+ ions


1st one
Reply 2193
Avatar for crc290
crc290
14
Original post by Shalo1
HAS ANYONE GOT THE JANUARY 2013 PAPERR?! ( and mark scheme)
:frown:(((( cant find it anywhere

(Pretty please)


Posted from TSR Mobile


Just search this thread, its already been posted multiple times...
Original post by Shalo1
HAS ANYONE GOT THE JANUARY 2013 PAPERR?! ( and mark scheme)
:frown:(((( cant find it anywhere

(Pretty please)


Posted from TSR Mobile


http://www.thestudentroom.co.uk/showthread.php?t=2264891
Original post by gooner1886
Is it not close to 80 odd? Like Unit 2 and 4?


No, I think 74 is the highest it's ever been for an A. If you look on this website, it tells you what raw mark corresponds to what UMS, and what the grade boundaries were for each exam:

http://www.aqa.org.uk/exams-administration/about-results/uniform-mark-scale/convert-marks-to-ums
Original post by flyylikejetz
That is the overall equation.
You will need to be able to use and recognise:

4H20 + 4e- --> 2H2 + 4OH-
2H2O + 4e- --> O2 + 4OH-

and the way to represent them



Original post by Dalts
you dont need to know a single one, they'll give you values etc, and just ask you questions on what they tell you



okay, thank you :smile:
is the salt bridge soaked in KNO3?
Original post by im7
I had a look at the specification about whether this unit was synoptic, and it said that all A2 units do have to have some synoptic element, and although this isn't an entirely separate assessment, it is sort of woven into the questions e.g. stuff like bond angles and oxidation states which are in the first unit.
However this unit doesn't have synoptic stuff from unit 4 (and probably most of unit 2 as these units both featured lots of organic chemistry) as unit 4 and 5 can be taken in any order


Thank you! :smile:
Anyone know the perfect definition for 'mean bond enthalpy'?

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you